Electroplating tail water coupling treatment system and method

Abstract

The invention discloses an electroplating tail water coupling treatment system and method, and belongs to the technical field of wastewater treatment. The first treatment area, the second treatment area and the aeration area are sequentially arranged from top to bottom, the cation exchange resin layer and the first electrode plate are arranged in the first treatment area, and the filler layer is arranged in the second treatment area, so that an ion exchange, electrochemistry and biodegradation coupled integrated treatment system is formed; when the system is used for treating the electroplating tail water, a large number of chemical agents do not need to be used, the operation cost is low, and heavy metal ions and organic pollutants in the electroplating tail water can be effectively removed.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a system and method for coupled treatment of electroplating tail water. Background Art

[0002] The electroplating process is a process that uses electrolysis to attach a layer of metal film to the surface of metal or other materials. Electroplating wastewater refers to the wastewater generated during the electroplating process, mainly including plated parts cleaning water, plating solution filtration and rinsing water, waste plating solution, ground washing wastewater, etc. These wastewaters contain a large amount of heavy metal ions, acid and alkali substances and organic matter. Once they are not properly managed and enter the environment, they will cause serious damage to human health and the ecological environment. At present, the main target of electroplating wastewater treatment is heavy metals, while the removal of electroplating organic matter has been ignored. The organic matter in the electroplating tail water includes complexing agents, stabilizers, dispersants, leveling agents, brighteners, etc. added during the electroplating process to improve the stability and quality of the coating. Most of these organic matter are difficult to remove, and traditional methods cannot effectively remove them, resulting in the problem of excessive organic matter content in the treated electroplating wastewater.

[0003] Advanced oxidation method is an emerging sewage treatment technology. It uses electricity, light radiation, and catalysts to produce highly active oxidizing substances, such as hydroxyl radicals, in the system, and then oxidizes and degrades large molecular refractory organic matter through addition, substitution, electron transfer, and bond breaking between hydroxyl groups and organic compounds. Electrochemical advanced oxidation method is flexible, does not require external additives, and has no secondary pollution. It is often used to treat refractory organic matter in wastewater. However, electrochemical advanced oxidation method can degrade organic matter, but it is difficult to mineralize it completely. After electrochemical advanced oxidation, although the concentration of some refractory organic matter is reduced, a large amount of intermediate products are produced and accumulated in the wastewater. If it is discharged directly, it still cannot meet the discharge requirements. The invention patent with publication number CN113716793A discloses a method for harmless treatment of electroplating tail water, and specifically discloses that the electroplating tail water treatment system can effectively reduce the COD in the electroplating tail water by sequentially undergoing secondary Fenton oxidation treatment, secondary biochemical treatment, primary Fenton oxidation treatment, and coagulation sedimentation treatment. However, the treatment method is complex, requires the addition of a large amount of chemicals, and has high operating costs.

[0004] Therefore, finding a more effective treatment system and method for removing organic matter contained in electroplating tail water has become an urgent problem to be solved. Summary of the invention

[0005] Based on the defects of the prior art, the purpose of the present invention is to provide a system and method for coupled treatment of electroplating tail water.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] In the first aspect, the present invention provides a coupled treatment system for electroplating tail water, comprising a treatment pool, wherein the treatment pool is provided with a water inlet and a water outlet, the water inlet of the treatment pool is connected to a water inlet pipe, and the water outlet of the treatment pool is connected to a water outlet pipe; the treatment pool is divided into a first treatment area, a second treatment area and an aeration area from top to bottom, the water inlet is located above the first treatment area, the water outlet is connected to the aeration area, a first filter plate is provided between the first treatment area and the second treatment area, a second filter plate is provided between the second treatment area and the aeration area, the first treatment area is provided with n cation exchange resin layers from top to bottom, a first electrode plate is provided between any two adjacent cation exchange resin layers, and one of any two adjacent first electrode plates is a cathode plate and the other is an anode plate; the first electrode plate is a grid structure, and the second treatment area is provided with m packing layers from top to bottom, and both n and m are integers not less than 3.

[0008] Preferably, a second electrode plate is arranged between any two adjacent filler layers, and one of the any two adjacent second electrode plates is a cathode plate and the other is an anode plate.

[0009] Preferably, the cathode plate is a titanium mesh, and the anode plate is a ruthenium-plated titanium mesh.

[0010] Preferably, the height of each cation exchange resin layer is 0.3-0.6 m, and the height of each packing layer is 1.3-1.8 m.

[0011] Preferably, the filler layer is paved with active biological fillers, and the active biological fillers include quartz stone and ceramic particles, and the mass ratio of the quartz stone to the ceramic particles is (0.5-3):1.

[0012] Preferably, a supporting layer is provided between the second filter plate and the packing layer.

[0013] Specifically, the filler in the supporting layer may be pebbles, the particle size of the filler in the supporting layer is 5 to 20 mm, and the height of the supporting layer is 0.2 to 0.4 m.

[0014] Preferably, the aeration zone is provided with a plurality of aeration devices, the aeration devices are connected with air inlet pipes, the air inlet pipes extend outside the treatment tank and are connected with air compressors.

[0015] Preferably, the treatment pool is provided with a reflux port, the reflux port of the treatment pool is located above the first treatment area, and the water outlet of the treatment pool is connected to the reflux port via a reflux pipe and a reflux pump.

[0016] Preferably, the water inlet pipe is provided with a water inlet valve, and the water outlet pipe is provided with a water outlet valve.

[0017] In a second aspect, the present invention provides a method for coupled treatment of electroplating tail water, which is implemented by the coupled treatment system for electroplating tail water described in the first aspect.

[0018] The electroplating tail water coupling treatment method comprises the following steps:

[0019] S1, injecting the mixed sewage into the treatment tank so that the mixed sewage in the treatment tank covers the second treatment area, and after aeration, discharging the treated sewage from the treatment tank;

[0020] S2, repeat step S1 until each packing layer forms a film successfully;

[0021] S3. After each anode plate and each cathode plate are connected to a DC power supply, the electroplating tail water is continuously input into the treatment pool where the biofilm is successfully formed, and aeration is performed from the bottom of the treatment pool.

[0022] Preferably, in step S1, the mixed sewage is prepared by mixing activated sludge and electroplating tail water, and the mass ratio of the activated sludge to the electroplating tail water is (0.5-1):1.

[0023] Preferably, in step S1, the aeration time is 12 to 36 hours, and the aeration volume is 1 to 3 L / min.

[0024] Preferably, in step S3, the input flow rate of the electroplating tail water is 300-600 mL / min, and the hydraulic retention time of the treatment tank is 3-6 h.

[0025] Preferably, in step S3, the current density of the DC power supply is 0.5-5 mA / cm 2 .

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention forms an "ion exchange + electrochemistry + biodegradation" coupled integrated treatment system by sequentially arranging a first treatment zone, a second treatment zone and an aeration zone from top to bottom, arranging a cation exchange resin layer and a first electrode plate in the first treatment zone, and arranging a filler layer in the second treatment zone; the system of the present invention is used to treat electroplating tail water, without the need to use a large amount of chemical agents, with low operating costs, and can effectively remove heavy metal ions and organic pollutants in the electroplating tail water. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of the electroplating tail water coupling treatment system provided by the present invention.

[0029] In the figure, 1-treatment tank, 2-water inlet pipe, 3-water inlet valve, 4-water outlet pipe, 5-water outlet valve, 6-first treatment area, 7-second treatment area, 8-aeration area, 9-first filter plate, 10-second filter plate, 11-cation exchange resin layer, 12-packing layer, 13-first electrode plate, 14-second electrode plate, 15-supporting layer, 16-aeration device, 17-air inlet pipe, 18-air compressor, 19-reflux pipe, 20-reflux pump. DETAILED DESCRIPTION

[0030] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and comparative examples, the purpose of which is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] See also Figure 1 The present invention provides a coupled treatment system for electroplating tail water, comprising a treatment pool 1, wherein the treatment pool 1 is provided with a water inlet and a water outlet, wherein the water inlet of the treatment pool 1 is connected to a water inlet pipe 2, on which a water inlet valve 3 is provided, and the water outlet of the treatment pool 1 is connected to a water outlet pipe 4, on which a water outlet valve 5 is provided; the treatment pool 1 is divided into a first treatment area 6, a second treatment area 7 and an aeration area 8 from top to bottom, wherein the water inlet is located above the first treatment area 7, the water outlet is connected to the aeration area 8, and the first treatment area 6 is connected to the second treatment area 7. 7, a first filter plate 9 is arranged between the second treatment zone 7 and the aeration zone 8, a second filter plate 10 is arranged between the second treatment zone 7 and the aeration zone 8, n cation exchange resin layers 11 are arranged in sequence from top to bottom in the first treatment zone 6, a first electrode plate 13 is arranged between any two adjacent cation exchange resin layers 11, and m packing layers 12 are arranged in sequence from top to bottom in the second treatment zone 7, one of any two adjacent first electrode plates 13 is a cathode plate and the other is an anode plate; the first electrode plate 13 is a grid structure, and n and m are both integers not less than 3.

[0032] The present invention forms an "ion exchange + electrochemistry + biodegradation" coupled treatment system by sequentially arranging the first treatment area 6, the second treatment area 7 and the aeration area 8 from top to bottom, arranging the cation exchange resin layer 11 and the first electrode plate 13 in the first treatment area 6, and arranging the filler layer 12 in the second treatment area 7. The system of the present invention is used to treat electroplating tail water without using a large amount of chemical agents, with low operating costs, and can effectively remove heavy metal ions and organic pollutants in the electroplating tail water.

[0033] In the first treatment area 6, the cation exchange resin layer 11 can adsorb heavy metal ions in the tail water. The cation exchange resin layer 11 adsorbing heavy metal ions is equivalent to loading catalytic components. When the cathode plate and the anode plate are powered, the cation exchange resin particles adsorbing heavy metal ions act as particle electrodes, and together with the cathode plate and the anode plate, they form a three-dimensional electrode system, and the difficult-to-degrade organic matter in the tail water is decomposed into small molecular organic matter through electrochemical catalytic oxidation. After passing through the first treatment area 6, the heavy metal ions and difficult-to-degrade organic matter in the tail water are effectively removed. In the second treatment area 7, the residual organic matter in the wastewater is degraded by aerobic organisms and mineralized into carbon dioxide and water.

[0034] In one embodiment, a second electrode plate 14 is disposed between any two adjacent filler layers 12; one of the two adjacent second electrode plates 14 is a cathode plate and the other is an anode plate; the second electrode plate 14 is a grid structure. After the second electrode plate 14 is energized, under the stimulation of the electric field, the microorganisms in the second treatment area 7 are more active, which can improve the degradation efficiency of the microorganisms on pollutants.

[0035] In the present invention, the cathode plate is a titanium mesh, and the anode plate is a ruthenium-plated titanium mesh.

[0036] In one embodiment, the cation exchange resin layer 11 is formed by laying at least one of D113 cation exchange resin, D001 cation exchange resin, D401 cation exchange resin, and 732 cation exchange resin.

[0037] After the anode plate and cathode plate are powered, the positively charged particles (ions or electrons) in the system solution will move toward the anode plate, causing the resin layer near the anode plate to be positively charged and anodized. At the same time, the negatively charged particles will move toward the cathode plate, causing the resin layer near the cathode plate to be negatively charged and cathodized. During the electrolysis process, oxygen reacts on the surface of the cathode plate and the cathodized resin layer to generate hydrogen peroxide. The reaction formula is as follows: 2 +2e - +2H + →H 2 O 2 The generated hydrogen peroxide can be converted into hydroxyl radicals through catalysis, indirectly oxidizing the difficult-to-degrade organic matter; the difficult-to-degrade organic matter undergoes oxidation reaction on the surface of the anode plate and the anodized resin layer.

[0038] In one embodiment, the height of the cation exchange resin layer 11 is 0.3 to 0.6 m, and the height of the packing layer 12 is 1.3 to 1.8 m.

[0039] In one embodiment, the filler layer 12 is paved with active biological fillers, wherein the active biological fillers include quartz and ceramic particles, and the mass ratio of quartz to ceramic particles is (0.5-3):1.

[0040] Specifically, the particle size of the active biological filler is 4-8 mm, and the mesh aperture of the electrode plate 13 is smaller than the particle size of the active biological filler.

[0041] In one embodiment, a supporting layer 15 is disposed between the second filter plate 10 and the packing layer 12 .

[0042] Specifically, the filler in the supporting layer 15 may be pebbles, and the particle size of the filler in the supporting layer 15 is 5 to 20 mm.

[0043] Specifically, the height of the supporting layer 15 is 0.2-0.4 m.

[0044] Specifically, the pore size of the second filter plate 10 is smaller than the filler particle size of the supporting layer 15 .

[0045] In one embodiment, the aeration zone 8 is provided with a plurality of aeration devices 16 , and the aeration devices 16 are connected to an air inlet pipe 17 , and the air inlet pipe 17 extends to the outside of the treatment tank 1 and is connected to an air compressor 18 .

[0046] Specifically, the aeration device 16 may be an aeration head, and the aeration direction of the aeration device 16 is upward, which is opposite to the water flow direction in the treatment tank 1, which is conducive to stabilizing aeration and improving the treatment efficiency of the system.

[0047] In one embodiment, the treatment pool 1 is provided with a reflux port, which is located above the first treatment area 6 , and the water outlet of the treatment pool 1 is connected to the reflux port via a reflux pipe 19 and a reflux pump 20 .

[0048] In the present invention, each first electrode plate 13, each second electrode plate 14, each first filter plate 9, and each second filter plate 10 can be fixed in the treatment tank 1 by insulating bolts, respectively.

[0049] Each first electrode plate 13 and each second electrode plate 14 has a terminal, and the side wall of the treatment tank 1 is provided with a through hole adapted to the terminal. The terminal is accommodated in the through hole, and the terminal is sealed with the inside of the through hole through a sealing ring.

[0050] In a second aspect, the present invention provides a method for coupled treatment of electroplating tail water, which is implemented by the coupled treatment system for electroplating tail water of the first aspect.

[0051] The electroplating tail water coupling treatment method comprises the following steps:

[0052] S1, injecting the mixed sewage into the treatment tank 1, so that the mixed sewage in the treatment tank 1 covers the second treatment area 8, and after aeration, discharging the treated sewage from the treatment tank 1;

[0053] S2, repeat step S1 until each packing layer 12 forms a film successfully;

[0054] S3. After each anode plate and each cathode plate are connected to a DC power supply respectively, the electroplating tail water is continuously input into the treatment pool 1 where the biofilm is successfully formed, and aeration is performed from the bottom of the treatment pool 1.

[0055] In one embodiment, in step S1, the mixed sewage is prepared by mixing activated sludge and electroplating tail water, and the mass ratio of the activated sludge to the electroplating tail water is (0.5-1):1.

[0056] In one embodiment, in step S1, the aeration time is 12 to 36 hours, and the aeration volume is 1 to 3 L / min.

[0057] In the present invention, the successful biofilm formation refers to the observation that a light yellow biofilm is attached to the filler layer 12 .

[0058] In one embodiment, in step S3, the input flow rate of the electroplating tail water is 300-600 mL / min, the hydraulic retention time of the treatment tank 1 is 3-6 h, and the gas-water ratio is (3-6):1.

[0059] It can be understood that the air-water ratio refers to the volume flow ratio between the air input into the treatment tank 1 through the aeration device and the electroplating tail water.

[0060] In one embodiment, in step S3, the current density of the DC power supply is 0.5-5 mA / cm 2 .

[0061] The electroplating tail water coupling treatment method of the present invention further comprises the following steps:

[0062] The effluent from the treatment tank 1 is tested regularly. If the effluent does not meet the discharge requirements, the reflux pump can be started to re-input the treated sewage into the treatment tank 1 for treatment.

[0063] The method of the present invention can be applied to the treatment of electroplating tail water after pretreatment and biochemical treatment, and can also be applied to industrial electroplating tail water without any treatment. Preferably, the method of the present invention is more suitable for treating electroplating tail water with a heavy metal content of ≤100 mg / L and a COD content of ≤500 mg / L.

[0064] The present invention provides the following examples to facilitate understanding of the present invention. The present invention provides these examples but is not intended to limit the scope of the claims.

[0065] In the following embodiments and comparative examples, the electroplating tail water comes from the electroplating tail water discharged from the same batch of the same factory, wherein the concentration of copper ions is 3.5 mg / L, the concentration of nickel ions is 2.1 mg / L, the COD content is 104 mg / L, the total nitrogen content is 35 mg / L, and the pH value is 7.5.

[0066] Example 1

[0067] The embodiment of the electroplating tail water coupling treatment system and treatment method of the present invention, the structure of the electroplating tail water coupling treatment system is as follows Figure 1 As shown, it includes a treatment pool 1, the treatment pool 1 is provided with a water inlet and a water outlet, the water inlet of the treatment pool 1 is connected to a water inlet pipe 2, the water inlet pipe 2 is provided with a water inlet valve 3, the water outlet of the treatment pool 1 is connected to a water outlet pipe 4, the water outlet pipe 4 is provided with a water outlet valve 5; the treatment pool 1 is divided into a first treatment area 6, a second treatment area 7 and an aeration area 8 from top to bottom, the water inlet is located above the first treatment area 7, the water outlet is connected to the aeration area 8, and a first treatment area 6 is provided between the first treatment area 6 and the second treatment area 7. A filter plate 9 is provided, a second filter plate 10 is provided between the second treatment zone 7 and the aeration zone 8, n cation exchange resin layers 11 are provided in sequence from top to bottom in the first treatment zone 6, a first electrode plate 13 is provided between any two adjacent cation exchange resin layers 11, m packing layers 12 are provided in sequence from top to bottom in the second treatment zone 7, one of any two adjacent first electrode plates 13 is a cathode plate and the other is an anode plate; the first electrode plate 13 is a grid structure, and n and m are both integers not less than 3.

[0068] A second electrode plate 14 is disposed between any two adjacent filler layers 12 ; one of any two adjacent second electrode plates 14 is a cathode plate and the other is an anode plate; the second electrode plate 14 is a grid structure.

[0069] Each cation exchange resin layer 11 is paved with D113 cation exchange resin, and the height of each cation exchange resin layer 11 is 0.5 m.

[0070] Each packing layer 12 is paved with active biological fillers, which include quartz and ceramic particles, and the mass ratio of quartz to ceramic particles is 1.5:1; the height of each packing layer 12 is 1.5m, and the particle size of the active biological fillers is 4-8mm.

[0071] A supporting layer 15 is arranged between the second filter plate 10 and the packing layer 12. The supporting layer 15 is paved with pebbles. The thickness of the pebbles is 5-20 mm. The height of the supporting layer 15 is 0.3 m.

[0072] The aeration zone 8 is provided with a plurality of aeration devices 16, and the aeration devices 16 are connected to an air inlet pipe 17, the air inlet pipe 17 extends to the outside of the treatment tank 1 and is connected to an air compressor 18, the aeration devices 16 are aeration heads, and the aeration direction of the aeration devices 16 is upward.

[0073] The treatment pool 1 is provided with a reflux port, which is located above the first treatment area 6 . The water outlet of the treatment pool 1 is connected to the reflux port via a reflux pipe 19 and a reflux pump 20 .

[0074] Each first electrode plate 13 , each second electrode plate 14 , each first filter plate 9 , and each second filter plate 10 can be fixed in the treatment tank 1 by insulating bolts, respectively.

[0075] Each first electrode plate 13 and each second electrode plate 14 has a terminal, and the side wall of the treatment tank 1 is provided with a through hole adapted to the terminal. The terminal is accommodated in the through hole, and the terminal is sealed with the inside of the through hole through a sealing ring.

[0076] The electroplating tail water coupling treatment method is implemented by the electroplating tail water coupling treatment system of this embodiment, and comprises the following steps:

[0077] S1, injecting the mixed sewage into the treatment tank 1, so that the mixed sewage in the treatment tank 1 covers the second treatment area 8, aerating at an aeration rate of 2L / min for 24 hours, and then discharging the treated sewage from the treatment tank 1;

[0078] S2, repeating step S1 until each packing layer 12 is successfully biofilmed, wherein the successful biofilming means that a light yellow biofilm is observed to be attached to the packing layer 12;

[0079] S3, connecting the terminals of each anode plate to the positive electrode of a DC power supply through a wire, connecting the terminals of each cathode plate to the negative electrode of the DC power supply through a wire, continuously inputting the electroplating tail water into the treatment pool 1 where the biofilm has been successfully formed, and aerating from the bottom of the treatment pool 1.

[0080] In step S1, the mixed sewage is prepared by mixing activated sludge and electroplating tail water, and the mass ratio of the activated sludge to the electroplating tail water is 0.5:1.

[0081] In step S3, the input flow rate of the electroplating tail water is 400 mL / min, the hydraulic retention time of the treatment pool 1 is 4 h, and the current density of the DC power supply is 2 mA / cm 2 , the gas-water ratio is 5:1.

[0082] Example 2

[0083] The difference between this embodiment and comparative example 1 is that in the embodiment, the cation exchange resin layer 11 is paved with D001 cation exchange resin.

[0084] Comparative Example 1

[0085] The difference between this comparative example and Example 1 is that in this comparative example, in step S3, each anode plate and each cathode plate in the first treatment area are not connected to a DC power supply respectively.

[0086] Comparative Example 2

[0087] The difference between this comparative example and Example 1 is that in this comparative example, the "cation exchange resin layer" is replaced by a ceramic layer formed by laying ceramic particles.

[0088] Comparative Example 3

[0089] The difference between this comparative example and Example 1 is that in this comparative example, in step S3, each anode plate and each cathode plate in the second treatment area are not connected to a DC power supply respectively.

[0090] During the implementation of the above-mentioned embodiments and comparative examples, the copper ion concentration, nickel ion concentration, COD content and total nitrogen content in the effluent of each treatment pool were tested, and the test results are shown in Table 1 below.

[0091] Table 1

[0092]

[0093] It can be seen from Table 1 that the electroplating tail water coupling treatment system provided in Examples 1 to 2 of the present invention, in conjunction with a specific process flow, can effectively remove heavy metals and organic pollutants in the electroplating tail water.

[0094] It can be seen from Example 1, Comparative Example 1 and Comparative Example 3 that the present invention utilizes ion exchange resins that adsorb heavy metal ions, cathode plates and anode plates to form three-dimensional electrodes, which can more effectively decompose difficult-to-degrade organic matter in the tail water into small molecular organic matter; under aeration conditions, the anode plates and cathode plates in the second treatment zone are energized to improve the degradation efficiency of pollutants by microorganisms.

[0095] It can be seen from Example 1 and Comparative Example 2 that the ion exchange resin in Example 1 can exchange and adsorb heavy metal ions in the tail water, while the ceramic layer of Comparative Example 2 has no obvious adsorption effect on heavy metal ions, resulting in the heavy metal ion concentration in the effluent of Comparative Example 2 being significantly higher than the heavy metal ion concentration in the effluent of Example 1; in addition, compared with Example 1, the first treatment zone of Comparative Example 2 weakens the degree of electrochemical reaction due to the lack of ion exchange process, which leads to a significant increase in COD and total nitrogen content in the effluent of Comparative Example 2.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. An electroplating tail water coupling treatment system, characterized in that: The invention comprises a treatment pool, wherein the treatment pool is provided with a water inlet and a water outlet, the water inlet of the treatment pool is connected to a water inlet pipe, and the water outlet of the treatment pool is connected to a water outlet pipe; the treatment pool is divided into a first treatment area, a second treatment area and an aeration area from top to bottom, the water inlet is located above the first treatment area, the water outlet is connected to the aeration area, a first filter plate is provided between the first treatment area and the second treatment area, a second filter plate is provided between the second treatment area and the aeration area, n cation exchange resin layers are provided in sequence from top to bottom in the first treatment area, a first electrode plate is provided between any two adjacent cation exchange resin layers, one of any two adjacent first electrode plates is a cathode plate, and the other is an anode plate; the first electrode plate is a grid structure, and m packing layers are provided in sequence from top to bottom in the second treatment area, and both n and m are integers not less than 3.

2. The electroplating tail water coupling treatment system according to claim 1, characterized in that: A second electrode plate is arranged between any two adjacent filler layers, and one of the second electrode plates is a cathode plate and the other is an anode plate.

3. The electroplating tail water coupling treatment system according to claim 1, characterized in that: The filler layer is paved with active biological fillers, and the active biological fillers include quartz stone and ceramic particles. The mass ratio of the quartz stone to the ceramic particles is (0.5-3):

1.

4. The electroplating tail water coupling treatment system according to claim 1, characterized in that: A supporting layer is arranged between the second filter plate and the packing layer.

5. The electroplating tail water coupling treatment system according to claim 1, characterized in that: The aeration zone is provided with a plurality of aeration devices, and the aeration devices are connected with air inlet pipes, and the air inlet pipes extend outside the treatment tank and are connected with air compressors.

6. The electroplating tail water coupling treatment system according to claim 1, characterized in that: The treatment pool is provided with a reflux port, the reflux port of the treatment pool is located above the first treatment area, and the water outlet of the treatment pool is connected to the reflux port through a reflux pipe and a reflux pump.

7. A method for coupled treatment of electroplating tail water, characterized in that: The method is implemented by the electroplating tail water coupling treatment system as described in any one of claims 1 to 6.

8. The electroplating tail water coupling treatment method according to claim 7, characterized in that: The steps include: S1, injecting the mixed sewage into the treatment tank so that the mixed sewage in the treatment tank covers the second treatment area, and after aeration, discharging the treated sewage from the treatment tank; S2, repeat step S1 until each packing layer forms a film successfully; S3. After each anode plate and each cathode plate are connected to a DC power supply, the electroplating tail water is continuously input into the treatment pool where the biofilm is successfully formed, and aeration is performed from the bottom of the treatment pool.

9. The electroplating tail water coupling treatment method according to claim 8, characterized in that: In step S1, the mixed sewage is prepared by mixing activated sludge and electroplating tail water, and the mass ratio of the activated sludge to the electroplating tail water is (0.5-1.0):1; the aeration time is 12-36h, and the aeration volume is 1-3L / min.

10. The electroplating tail water coupling treatment method according to claim 8, characterized in that: In step S3, the input flow rate of the electroplating tail water is 300-600 mL / min, the hydraulic retention time of the treatment pool is 3-6 h, and the current density of the DC power supply is 0.5-5 mA / cm 2 .

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